This invention relates to a method of producing a flexible microcircuit having conductive paths or runs for connection between a device such as a semiconductor and a connector for joining with hard wiring.
There are, of course, many methods of fabricating flexible microcircuits and which include processing steps with photoresist methods to produce conductive runs therein. Many, however, are not optimized or are used with larger flexible circuits that can be more easily produced in commercial quantities.
In particular, it has been difficult to fabricate a flexible microcircuit of the size usable in attaching a distal end thereof to a semiconductor device, such as a JFET or ISFET to produce a freely suspended device on the end of the flexible microcircuit. The flexible microcircuit for such use must be specifically manufactured and must have, at its distal ends extremely minute holes for providing connection with the semiconductor device.
An example of such a semiconductor device is in U.S. Pat. No. 4,180,771 of Guckel et al. Such devices are capable of being introduced into a person's blood stream for in vivo measurements of pH etc., therefore, must be extremely minute as well as flexible so that the semiconductor device, as well as the flexible circuit holding that device can enter the patient's blood stream without creating a hazardous interference with the natural flow of blood therein.
The distal end of such a flexible microcircuit to be connected to the JFET must have a plurality of holes having diameters of about 0.002" in order to be connectible thereto, and the proximal end thereof adaptable for connection to hard wiring devices. Because of the size of the microcircuit itself and the requirement for extremely minute yet accurately positioned holes, the fabrication of such microcircuit is difficult.